首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   5563篇
  免费   379篇
  国内免费   39篇
耳鼻咽喉   129篇
儿科学   138篇
妇产科学   122篇
基础医学   832篇
口腔科学   163篇
临床医学   492篇
内科学   1166篇
皮肤病学   56篇
神经病学   308篇
特种医学   147篇
外国民族医学   3篇
外科学   904篇
综合类   119篇
一般理论   4篇
预防医学   358篇
眼科学   123篇
药学   482篇
中国医学   56篇
肿瘤学   379篇
  2024年   8篇
  2023年   63篇
  2022年   159篇
  2021年   253篇
  2020年   155篇
  2019年   204篇
  2018年   263篇
  2017年   164篇
  2016年   187篇
  2015年   203篇
  2014年   265篇
  2013年   313篇
  2012年   552篇
  2011年   494篇
  2010年   271篇
  2009年   202篇
  2008年   288篇
  2007年   314篇
  2006年   269篇
  2005年   242篇
  2004年   200篇
  2003年   189篇
  2002年   162篇
  2001年   58篇
  2000年   59篇
  1999年   51篇
  1998年   46篇
  1997年   24篇
  1996年   27篇
  1995年   12篇
  1994年   23篇
  1993年   20篇
  1992年   24篇
  1991年   24篇
  1990年   18篇
  1989年   19篇
  1988年   22篇
  1987年   21篇
  1986年   7篇
  1985年   13篇
  1984年   7篇
  1983年   6篇
  1980年   6篇
  1979年   4篇
  1978年   6篇
  1977年   6篇
  1974年   9篇
  1973年   10篇
  1972年   3篇
  1971年   4篇
排序方式: 共有5981条查询结果,搜索用时 46 毫秒
31.
Recognition of death anxiety experienced by patients who have survived violence and threats to life during war is of strong importance in delivery of best care for veterans experiencing health stressors. The aim of the study was to explore the death anxiety experience of veterans from the Iran–Iraq war. Using a phenomenological approach, 11 war veterans were interviewed related to death anxiety experiences. Four major themes included afterlife fears; alienated farewell; ambiguous separation; and physical dissolution. Patients who have been exposed to death trauma in the battlefield may carry added burden from unique cognitions and fears related to personal death.  相似文献   
32.
Persistent renal and extrarenal immune changes after severe ischemic injury   总被引:7,自引:0,他引:7  
BACKGROUND: Renal ischemia/reperfusion (I/R) injury is associated with delayed graft function and decreased long-term allograft function. However, most experimental studies evaluating renal I/R injury have focused on acute events after ischemia. T cells are potential candidates to link preservation injury, alloimmunity, and fibrosis. We hypothesized that severe renal I/R injury would generate long-term kidney damage and immune changes. METHODS: C57BL/6 mice underwent 60 minutes of warm unilateral I/R injury or sham surgery and were studied for 6 weeks. Serum creatinine, renal histology, and albumin excretion were measured. Phagocyte infiltration, CD4+ infiltration, renal cytokine expression, and splenic lymphocyte intracellular cytokine production were also measured in mice at 6 weeks. RESULTS: Serum creatinine levels rose following 60 minutes of unilateral I/R injury compared to sham mice. Histologic analysis of ischemic kidneys at 6 weeks revealed a pronounced loss of tubular architecture and infiltration of inflammatory cells. Phagocyte and CD4+ T-cell infiltration were significantly increased in ischemic kidneys. This was accompanied by a significant increase in interleukin (IL)-1beta and regulated upon activation, normal T-cell expressed and secreted (RANTES) expression. Despite similar splenic CD4 and CD8 numbers, intracellular cytokine staining of T cells revealed a significant increase in interferon-gamma (IFN-gamma) in I/R injury mice compared to sham mice. CONCLUSION: Persistent renal and extrarenal immune responses occur after a single episode of severe I/R injury. These immune processes resulting from injury could in turn have long-term consequences on progression of renal disease in transplanted and native kidneys.  相似文献   
33.
34.

Summary

Here we report that abnormal brain white matter and, to a lesser extent, albuminuria are associated with reduced bone mineral density in the hip, spine, and total body in men and women. These findings may explain the increased hip fracture risk reported in some studies in association with microvascular disorders.

Introduction

Markers of microvascular disease have been individually associated with increased risk of osteoporotic fractures in some studies. Here, we examine whether these markers are associated with reduced bone mineral density (BMD) individually and together.

Methods

BMD testing using dual x-ray absorptiometry of the hip, lumbar spine, and total body was performed in 1473 participants from the Cardiovascular Health Study (mean age ~ 78 years): 1215 were assessed for urinary albumin-creatinine ratio, 944 for abnormal white matter disease (AWMD) by brain MRI, and 541 for retinal vascular disease with fundus photographs. Linear regression models were used to evaluate the cross-sectional association of each marker with BMD accounting for potentially confounding factors.

Results

AWMD was associated with lower hip, spine, and total body BMD in women (β ?3.08 to ?4.53; p < 0.01 for all) and lower hip and total body BMD in men (β ?2.90 to ?4.24; p = 0.01–0.03). Albuminuria was associated with lower hip (β ?3.37; p = .05) and total body (β ?3.21; p = .02) BMD in men, but not in women. The associations of AWMD and albuminuria with BMD persisted with mutual adjustment and appeared to be additive to each other. Retinal vascular disease was not associated with BMD in men or women.

Conclusion

AWMD and, to a lesser extent, albuminuria were independently associated with lower BMD, suggesting that microvascular disease may play a role in the pathogenesis of reduced BMD. These findings need to be confirmed by longitudinal studies.
  相似文献   
35.
36.
Introduction  Kaposi’s sarcoma (KS) is one of the most common tumors to occur in kidney recipients, especially in the Middle East countries. Limited data with adequate sample size exist about the development of KS in living kidney recipients. Methods  Therefore, we made a plan for a multicenter study, accounting for up to 36% (n = 7,939) of all kidney transplantation in Iran, to determine the incidence of KS after kidney transplantation between 1984 and 2007. Results  Fifty-five (0.69%) recipients who developed KS after kidney transplantation were retrospectively evaluated with a median follow-up of 24 (1–180) months. KS occurred more often in older age when compared to patients without KS (49 ± 12 vs. 38 ± 15 years, P = 0.000). KS was frequently found during the first 2 years after transplantation (72.7%). Skin involvement was universal. Furthermore, overall mortality rate was 18%, and it was higher in patients with visceral involvement compared to those with mucocutaneous lesions (P = 0.01). However, KS had no adverse affect on patient and graft survival rates compared to those without KS. Forty-four patients with limited mucocutaneous disease and four with visceral disease responded to withdrawal or reduction of immunosuppression with or without other treatment modalities. Renal function was preserved when immunosuppression was reduced instead of withdrawn in patients with and without visceral involvement (P = 0.001 and 0.008, respectively). Conclusion  The high incidence of KS in this large population studied, as compared to that reported in other transplant patient groups, suggests that genetic predisposition may play a pathogenetic role.  相似文献   
37.
OBJECTIVES: We examined the incidence of facial nerve stimulation in a population of patients with otosclerosis implanted with the Nucleus 22, Clarion 1.2, or Clarion High Focus (CHF) device. STUDY DESIGN AND SETTING: A retrospective chart review was used for 147 patients who had been implanted with electronic cochlear devices at the University of Minnesota between June 1986 and February 2001. Seventy-four patients were implanted with the Nucleus 22, 41 patients were implanted with the Clarion 1.2 (without a positioner), and 32 patients were implanted with the CHF I or II. RESULTS: Eleven (14.9%) of the 74 patients implanted with the Nucleus 22 device had facial stimulation. There were 9 patients with otosclerosis. Seven (78%) of the 9 patients with otosclerosis had facial stimulation. One (2.4%) of the 41 patients implanted with the Clarion 1.2 device (without a positioner) had facial stimulation and that 1 (100%) patient in the group had otosclerosis. There were 4 patients in the CHF group with otosclerosis. One patient experienced stimulation, but it was possible to decrease maximum current levels and still use the electrode pair. CONCLUSION: Facial stimulation appears to be less problematic in patients with otosclerosis implanted with the CHF devices.  相似文献   
38.
Effects of spinal cord injury on semen parameters   总被引:1,自引:0,他引:1  
OBJECTIVE/BACKGROUND: Neurogenic reproductive dysfunction in men with spinal cord injury (SCI) is common and the result of a combination of impotence, ejaculatory failure, and abnormal semen characteristics. It is well established that the semen quality of men with SCI is poor and that changes are seen as early as 2 weeks after injury. The distinguishing characters of poor quality are abnormal sperm motility and viability. In the majority of the men with SCI, the sperm count is not abnormal. We elaborate on the effects of the SCI on semen parameters that may contribute to poor motility and poor viability. METHODS: Review. DESIGN: PubMed and MEDLINE databases were searched using the following key words: spinal cord injuries, fertility, sexual dysfunction, and spermatogenesis. All literature was reviewed by the team of authors according to the various stages of sperm development and transport in the male reproductive cycle. FINDINGS: The cause of asthenozoospermia appears to be multifactorial. CONCLUSION: Current literature does not support the preeminence of a single factor relating to neurogenic reproductive dysfunction in men with SCI. After SCI, there is ample evidence of disturbance of sperm production, maturation and storage, and transport due to an abnormal neuroendocrine milieu. Semen quality seems to be primarily affected by changes to the seminal plasma constituents, type of bladder management, and the neurogenic impairment to the ejaculatory function. Further focused and structured studies are required.  相似文献   
39.
We report a case of anomalous course of the right coronary artery in the wall of right atrium which was encountered during coronary artery bypass surgery. As the stenotic lesion in the vessel was proximal, the large posterior descending branch of the right coronary was grafted. Such an anomalous course of the right coronary artery has not been previously described in the literature and lack of knowledge of such an abnormal course may result in inadvertant damage during cannulation of the inferior vena cava or coronary sinus.  相似文献   
40.
BACKGROUND: Ischemia-reperfusion injury (IRI) is the major cause of delayed graft function in renal allografts. The present study was performed to investigate the validity of serum creatinine (SCr) level as an indicator of postischemic renal dysfunction in mice. METHODS: Renal IRI or sham surgery was induced in C57BL/6 mice, and SCr level and inulin clearance (Cin) were measured between 24 hr and 7 days after ischemia. RESULTS: Cin in IRI mice was reduced 75% at 72 hr after ischemia in association with a nearly threefold increase in SCr level. Cin in IRI mice did not recover between 72 hr and 7 days after ischemia, even though SCr level at 7 days was not different between control and IRI mice. In IRI mice, SCr level measured at 24, 48, and 72 hr after ischemia correlated inversely with Cin measured at 72 hr, but not 7 days, after ischemia. CONCLUSIONS: SCr level in the early postischemic period (24-72 hr) seems to be a valid indicator of early postischemic renal dysfunction, and that renal function remains markedly depressed at 7 days despite suggestion from the SCr value that renal function is improving.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号